From 2e1e65a5c0a9f8ba5b7b3ce848176482ba4da654 Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Wed, 4 Oct 2017 21:19:33 +0300 Subject: [PATCH] Fixed buffer overread with unix sockets after accept(). Some OSes (notably macOS, NetBSD, and Solaris) allow unix socket addresses larger than struct sockaddr_un. Moreover, some of them (macOS, Solaris) return socklen of the socket address before it was truncated to fit the buffer provided. As such, on these systems socklen must not be used without additional check that it is within the buffer provided. Appropriate checks added to ngx_event_accept() (after accept()), ngx_event_recvmsg() (after recvmsg()), and ngx_set_inherited_sockets() (after getsockname()). We also obtain socket addresses via getsockname() in ngx_connection_local_sockaddr(), but it does not need any checks as it is only used for INET and INET6 sockets (as there can be no wildcard unix sockets). --- src/core/ngx_connection.c | 4 ++++ src/event/ngx_event_accept.c | 8 ++++++++ 2 files changed, 12 insertions(+) diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c index 392fc3587..9a747589c 100644 --- a/src/core/ngx_connection.c +++ b/src/core/ngx_connection.c @@ -165,6 +165,10 @@ ngx_set_inherited_sockets(ngx_cycle_t *cycle) continue; } + if (ls[i].socklen > (socklen_t) sizeof(ngx_sockaddr_t)) { + ls[i].socklen = sizeof(ngx_sockaddr_t); + } + switch (ls[i].sockaddr->sa_family) { #if (NGX_HAVE_INET6) diff --git a/src/event/ngx_event_accept.c b/src/event/ngx_event_accept.c index 87447d089..775637090 100644 --- a/src/event/ngx_event_accept.c +++ b/src/event/ngx_event_accept.c @@ -164,6 +164,10 @@ ngx_event_accept(ngx_event_t *ev) return; } + if (socklen > (socklen_t) sizeof(ngx_sockaddr_t)) { + socklen = sizeof(ngx_sockaddr_t); + } + c->sockaddr = ngx_palloc(c->pool, socklen); if (c->sockaddr == NULL) { ngx_close_accepted_connection(c); @@ -440,6 +444,10 @@ ngx_event_recvmsg(ngx_event_t *ev) c->type = SOCK_DGRAM; c->socklen = msg.msg_namelen; + if (c->socklen > (socklen_t) sizeof(ngx_sockaddr_t)) { + c->socklen = sizeof(ngx_sockaddr_t); + } + #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_active, 1); #endif